Disposable garments are generally well known in the art and have become an important and an essentially indispensable sanitary protection item, most particularly in the field of infant and child care where disposable diapers provide for the absorption and containment of urine and other body exudates. Present commercially available disposable diapers are generally unitary, preshaped and prefolded, and comprised of a porous facing layer, a fluid impervious backing sheet with an absorbent material disposed therebetween. These presently available commercially available disposable diapers have met a particular need and have become ever increasingly popular. However, even though the presently available disposable diapers are efficient and effective they have several drawbacks that have been identified by mothers of infants wearing the diapers. These mothers have strongly voiced their desire to be able to obtain disposable diapers that are aesthetically neat and attractive when on their infant or child. The aesthetically neat criteria have been identified as including a trim, slim fit, and a neat fitting waist and legs that do not allow leakage of urine or feces. It has also been found that mothers do not want their children to look rumpled, bulky, or messy. In addition, these mothers have expressed a desire to either have a disposable diaper that fits more sizes of babies or to have disposable diapers provided in more sizes.
Another drawback identified by these mothers has been the problem associated with skin irritation caused by urine, feces, or moisture trapped next to the skin. They have again been very vocal in their desire to obtain disposable diapers that avoid or solve this problem.
Another major drawback is associated with the methods provided to secure the diaper around the baby. The method most utilized in present commercially available disposable diapers is the plastic sealable tape. Initially, the fastening tapes introduced on disposable diapers were not resealable, which meant that when the mother wished to check the diaper for wetness or to adjust the fit, the tapes could not be resealed. This, in turn, meant that the diaper, if not ready to be changed, would have to be thrown away. Presently, disposable diapers use tapes that are manufactured to be resealable. However, it has been found that the tapes presently used are subject to contamination by baby powder or baby oil or other substances which prevent them from resealing, or in the worst case, prevent them from sealing upon initial use. The mothers indicate that they want disposable diapers that have fasteners that are not subject to contamination, that are always resealable and that are not easily unfastenable by babies. The attempt to provide tapes that are always resealable has caused some manufacturers to utilize stronger adhesives on the tapes. Unfortunately, however, the stronger adhesives have a tendency to tear the outer cover which may also cause the diaper to be unusable.
Furthermore, the fastening tapes used on the present disposable diaper can also have a detrimental effect upon fit. Because the tapes are made to be sealable on any portion of the outer cover, and there is no indication to mothers where the tapes should be sealed, the tapes are very often sealed to the outer cover at the wrong position which has several detrimental effects. First, the diaper does not fit on the baby properly, for example, if too loose, the diaper falls down or droops at the waist, or if too tight, causes strain in the outer cover which can make the baby uncomfortable. Second, the improper positioning of the tapes can cause the leg openings to gap thus causing leakage. Third, in an attempt to reposition the tapes to correct the above problems mothers have found that there is an increased potential to contaminate the tapes thus causing the disposable diaper to be unusable.
The attempts to solve the drawbacks associated with present disposable diapers have extended over several years and include several different methods. One method to improve fit involves geometrical folding of rectangular diapers for the purpose of narrowing the apparent width in the crotch area. One method is taught in U.S. Pat. No. Re. 26,151 to Duncan et al. in which a rectangular diaper is provided with parallel longitudinal folded box pleats and a loose overlying flap along each side. Another method is taught in U.S. Pat. No. 3,196,874 to Hrubecky, in which a rectangular diaper is provided with triangular-shaped infolds in the crotch area. These two methods permit the diaper to be more easily fitted to the child, however, problem areas remain. First, the prefolded rectangular diaper results in increased bulk between the legs causing discomfort to the infant. Second, the nonconforming bulk prevents the diaper from closely conforming to the legs leaving gaps which permit leaks to occur. Third, the nonconforming sides tend to pull the waist down at the sides thereby causing the diaper to gap at the front of the waist where leaks can also occur. In addition, the gapping at the front waist contributes to making the diaper appear bulky, sloppy and messy.
To solve the resulting problems associated with the nonconforming bulk between the legs, methods, including reducing the width of the absorbent pad in the crotch area, were tried. However, because the materials used in constructing disposable diapers are relatively nonconformable, a close fit around the thighs is difficult to achieve and undesirable gaps still have a tendency to occur. In addition, the reduced width of the absorbent pad reduces the available absorbent capacity which also further increases the potential for leakage. In an attempt to reduce leakage, U.S. Pat. No. 3,860,003 to Buell provides the diaper edges with elasticized, flexible flaps between the elasticized line and the edge of the absorbent pad an the crotch.
Again, an attempt to solve one problem results in the emergence of another problem. Elasticized flaps provide a tight seal at the thighs because the tensioned elastic presses the easily deformable flaps into close contact with the legs. However, the tight seal at the thighs can have several causal effects. First, the tight seal can cause urine to collect near the diaper edges which can permeate into the area between the flap and the skin where it can cause skin irritation. Second, because it is necessary to reduce the absorbent pad width in order to provide the required flap width, the remaining absorbent becomes excessively wet and leaks can still occur. Third, when the reduced width of the absorbent becomes excessively wet, it tends to separate and bunch up at the bottom of the crotch thus hindering fluid transfer to unused portions of the absorbent pad.
To solve the problems associated with elasticized flaps a new and improved disposable diaper is taught in U.S. Pat. No. 4,050,462 to Woon et al. in which the diaper is elasticized only along the edges in a narrowed crotch area in a manner to give a more conformable leg fit as well as improved functional absorbent capacity. This is achieved by attaching the elastic immediately adjacent to the edges of the absorbent pad and also bonding the absorbent pad surface to the backing or facing material in that area to unitize the structure. This causes the absorbent pad to contract when the elastic contracts thus producing gross transverse rugosities, inter alia, in the crotch area. These gross transverse rugosities increase the effective absorbent capacity of the absorbent pad by decreasing the tendency of the absorbent to separate and increasing the wicking characteristics of the absorbent.
The present application teaches an improved disposable diaper which is anatomically form-fitting and anatomically self-adjusting to provide an attractively slim, trim diaper for the baby to wear. The diaper provided by the present invention is trim, does not gap at the legs or waist, and has virtually contamination-proof refastenable fixed position fasteners. The multilayer absorbent structure of the present invention provides improved absorbent capacity, with novel construction and absorbent composition. Furthermore, the disposable diaper as provided by the present invention is breathable and at the same time highly resistant to leakage.